Lasianthaea fruticosa (L.) K.M.Becker var. fruticosa
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Authority
Becker, Kenneth M. 1979. A monograph of the genus Lasianthaea (Asteraceae). Mem. New York Bot. Gard. 31 (2): 1-64.
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Family
Asteraceae
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Scientific Name
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Description
Species Description - Shrubs or small trees, soft-wooded and usually slender-stemmed, sometimes straggling or chmbing, or occasionally half-shrubs, (0.3-)1.5-6(-7) m high; young branches varying from nearly glabrous to densely villous. Leaves with petiole (0.5-)1-4(-4.5) cm long; blade thin to firm, lance-ovate to ovate, varying to lanceolate and broadly ovate, (3-)5-16(-22) cm long, 1.5-9(-12) cm wide, sparsely strigillose to pilose below, triplinerved or occasionally subpenninerved. Inflorescence (l-)3-9-headed. Peduncles 0.5-9(-14) cm long, slender to stout; heads 2-3.5 cm wide across extended rays. Involucre usually campanulate to broadly campanulate, varying to narrowly campanulate and hemispherical, 0.5-1.3 cm high, (0.5-)0.7-1.9 cm wide, phyllaries in 2-3 equal or slightly graduated series. Outer phyllaries usually reticulate and often slightly amphated above, ovate-oblong to lance-ovate in outline, 5-16 mm long, 1-8 mm wide, middle phyllaries usually conspicuously nerved, inner phyllaries 5-9 mm long, 1-4.5 mm wide. Rays (5-)8-13, lamina 7.5-15(-20) mm long, 2.5-7 mm wide. Disc florets 35-100, 5-8 mm long. Disc achenes with body 3.5-5 mm long, 0.9-1.5 mm wide, awns (2-)3-5 mm long, not exserted or exserted up to 5 mm from ripe heads. Ray achenes with body 3.0-4.2 mm long, 1.0-1.5 mm wide. Chromosome number, from meiotic material, n = 11.
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Discussion
Bidens frutescens Mill, Gardn. Diet. ed. 8, no. 4, 1768. Zexmenia frutescens (Mill.) Contr. Gray Herb. 52: 50, 1917. Z. frutescens var. genuina Blake, Contr. Gray Herb. 52: 51, 1917. Type: Specimen in Herb. Sloane 316.75 from Chelsea Garden, 1737, raised from seed sent from Carthagena (COSTA RICA) (holotype: BM; photos: G H, MICH, NY, US (2)). Lipochaeta monocephala DC, Prodr. 5: 610, 1836. Zexmenia monocephala (DC.) Sch. Bip. in Seem., Bot. Voy. Herald 306, 1856. Type: Cultivated, Hort. Par. (holotype: G; photos: GH, US(2); drawing: GH).
Zexmenia costaricensis Benth. in Oersted, Vidensk. Meddel. 1852: 95, 1853.
Zexmenia nicaraguensis "Benth." ex C. Muell. in Walp., Ann. Bot. 5: 226, 1858 (sphalm.). Type: COSTA RICA: "In monte Aguacate," Nov 1846, Oersted 8516 (holotype: K(herb. Benth.); fragment: GH; fragment and photo: US(2); photos: G H , US; isotype: C; tracing: GH, W).
Zexmenia villosa Polak., Linnaea 41: 579, 1877. Zexmenia costariensis Benth. var. villosa (Polak.) Blake, Jour. Bot. 53: 14, 1915. Zexmenia frutescens (Mill.) Blake var. villosa (Polak.) Blake, Cont. Gray Herb. 52: 51, 1917. Type: COSTA RICA: San Jose: San Jose, ad margines hortorum, Nov, Polakowsky 466 (holotype: W ; photos: F, US; isotype: BM; photos: GH, US).
Zexmenia elegans Sch. Bip. ex W . W . Jones, Proc. Amer. Acad. 41: 157, 1905. Type: MEXICO: Veracruz: Mirador, Nov 1841, Liebmann 378 (holotype: G H ; photo: US; isotypes: C(2); photos: (of one sheet at C) F, MICH, NY (of both sheets at C) US, G, K, NY, P).
Zexmenia elegans Sch. Bip. var. kellermannii Greenm., Field Col. Mus. Bot. Ser. 2: 348, 1912. Type: GUATEMALA: Izabal: Los Amates, 15 Feb 1908, Kellerman 7612 (holotype: F; isotypes: NY, US).
Zexmenia purpusii Brandeg., Univ. Calif. Publ. Bot. 6: 75, 1914. Type: MEXICO: Chiapas: Cerro del Boqueron, Sep 1913, Purpus 6660 (holotype: UC; photos: ENCB, MEXU).
Zexmenia macropoda Blake, Contr. U. S. Nat. Herb. 22: 634, 1924. Type: GUATEMALA: Solola, 25 Jan 1915, Holway 109 (holotype: G H ; photo: ENCB).
Lasianthaea fruticosa var. fruticosa is a basically Central American variety which reaches southeastern Mexico. It occurs throughout its range in a wide variety of habitats and altitudinal situations. It is variable in pubescence of stems, leaves, and phyllaries, in head size, and in peduncle length. Degree of pubescence seems to be related to altitude. Plants from lower elevations (down to sea level) are less pubescent, often almost glabrous, while plants from higher elevations (to pine and cloud forest) tend to be more pubescent, often densely so. Length of outer phyllaries is also variable, being usually equal or subequal to the inner, but varying to decidedly longer or shorter.
Several of the variants and extreme forms of L. fruticosa var. fruticosa have been given taxonomic recognition at the specific level in the past. Zexmenia monocephala represents an extreme in inflorescence reduction, occasionally seen throughout the range of the variety, especially in heads produced from upper leaf axils, where only one head, rather than 3-12, is produced. Zexmenia macropoda, with long, stout peduncles and large heads represents another extreme. Cronquist & Sousa 10458 exhibits variation in head size within one collection, ranging from that found in the type of Z. macropoda (Holway 109) down to heads one-third that size. Zexmenia villosa represents a particularly densely pubescent form well within the normal range of variation for the variety. Zexmenia elegans represents a relatively glabrous, narrow-leaved form with shghtly imbricate involucres commonly found in southeastern Mexico but also occasionally in Central American populations. Collections which are of particular interest with regard to intermediacy with varieties michoacana and fasciculata are cited below.
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Distribution
Wet or dry thickets, roadsides, slopes, wood edges, often in secondary communities; in lowland perennial and subperennial, tropical deciduous, pineoak, and cloud forest. Oaxaca and Veracruz in Mexico (Map 1) to Panama, rarely in northern Venezuela, at altitudes from 0-1800 m. Blooming year round.
Mexico North America| Venezuela South America| Panama Central America| Honduras Central America|